My Auxiliary fan is not working in conjunction with engine temp. I have a Manual Transmission, 86 300E. The fan IS working - it comes on when I turn on the A/C, and then works properly in that mode.

It will not come on when the temperature of the engine goes up (and the A/C is off), and therefore my car burps coolant through the overfill tube occasionally when I park it and without a little air from the fan, it gets hotter than normal. Reading other posts I am guessing that I need to replace a sensor, but I'm getting conflicting information. Anyone know which one and where is it? Is there a way to test that sensor?

Any help would be appreciated.

okay men, this is one we can fix...... not all at once though......

I am not sure about 86, but in later years, the low speed is controlled by the engine temp and ac cuton, the high speed is controlled only by a/c temp or pressure. NOW... someone correct me so we can begin the diagnosis....

engine temp switch? or low speed fan relay?.... again 86

Thanks - I appreciate the input - hopefully someone can chime in with your answers.

I ordered both and then replaced the engine temperature switch first, and that did the trick! Thanks for the help!